Abstract: A process for the recovery of valuable metals or their compounds from an aqueous medium, such as a metals refinery process waste solution. Metals are recovered in water-insoluble form from aqueous solutions of metal salts by contacting the aqueous solution with a killed fungus of the type commonly called molds for a period of time sufficient to convert soluble metal components in the aqueous solution to a water insoluble form sequestered by the dead fungus. After treatment, metals-containing fungus is separated from the treated aqueous medium and processed for the recovery of metal values.

Abstract: Platinum, palladium and other precious metals are recovered from aqueous media containing precious metal ions in solution by contacting the metal-containing solution with a proteinaceous material selected from the group consisting of feathers, hair, hoof meal and horn meal to collect the metals in concentrated insoluble form, and recovering metal from the proteinaceous material.